I believe the landscaping of areas like pershing sq is much more difficult cuz plants & trees have to sit on what's really a concrete pad. So unlike the original Pershing sq, which had nothing but dirt under it, the current Pershing Sq is located above a large underground parking structure.
I think there's underground parking lots below many parts of the civic ctr mall too. That means the weight of trees in particular have to be factored in to how much can be planted per sq ft.
I know there's a woodsy like garden on the rooftop of the former New Otani hotel in Little tokyo, but I believe even in that case trees & plants probably are affected by the fact they're located in a concrete tub. So I'd guess the size of trees & their root system can't be allowed to grow too large.
Best thing about the proposed civic ctr mall is it finally will get rid of the big surface parking lot directly west of city hall. That area of pavement has been a blight on the hood for yrs & yrs, & a very weak foreground for a bldg as important as city hall.
As for the new economics, I don't know if huge highrise residential projs can ever pencil out now that the psf pricing of condos----& apts too----is way lower than it was a few yrs ago.
The devlpr of the 717 olympic apt tower said his proj wouldn't make sense in the current economic climate----& he made that claim 2 yrs ago. I know the previous owner of the Roosevelt bldg who wanted to convert it to condos over 8 yrs ago dropped his plans cuz housing prices at that time had yet to soar as they would around 2003.
Sad that the devlpr of the park fifth proj may be experiecing deja vu all over again, since his original proposal in the 1980s for the land across from Pershing Sq also got walloped & then cancelled by the economy back then.
So lowrise wood framed----or primarily wood framed----bldgs like the sakura, the medallion, & the awesome, fantastic faux Euro ones built by GH Palmer will be the most anyone can expect to see rise in DT over the next several yrs. Even in that case, look at how the devlpr of the medallion struggled to get his proj under actual construction.